1. Energy loss, a novel biomechanical parameter, correlates with aortic aneurysm size and histopathologic findings 
Jennifer Chung, MD, Kevin Lachapelle, MD, Evan Wener, BASc, Raymond Cartier, MD, Benoit De Varennes, MD, Richard Fraser, MD, MSc, Richard L. Leask, PhD 
The Journal of Thoracic and Cardiovascular Surgery 
Volume 148, Issue 3, Pages (September 2014)
DOI: /j.jtcvs
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2. Figure 1
The stress–strain relationship of the ascending aorta and definitions of 2 biomechanical parameters: the apparent modulus of elasticity and the percentage of energy loss per cycle.
The Journal of Thoracic and Cardiovascular Surgery  , DOI: ( /j.jtcvs )
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3. Figure 2
A, The effect of aortic diameter on energy loss. B, Energy loss rapidly increases with greater variability for aortic diameters >55 mm. The average energy loss in aortas <55 mm and >55 mm was 26.5% ± 2.7% and 35.5% ± 5.8%, respectively (P = .0001).
The Journal of Thoracic and Cardiovascular Surgery  , DOI: ( /j.jtcvs )
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4. Figure 3
At >5.5 cm in size, energy loss rapidly increased, with greater variability. The red dots represent aortas indistinguishable by aortic size but with a wide range in energy loss. Aortas with low energy loss, box (A), displayed normal histologic features with preserved elastic laminae (brown to black) and intact smooth muscle cells (red to purple). In contrast, aortas with elevated energy loss, box (B), display fragmentation of elastin, loss of smooth muscle cells, and replacement with collagen (yellow).
The Journal of Thoracic and Cardiovascular Surgery  , DOI: ( /j.jtcvs )
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5. Figure 4
Once the aortic size has been indexed to the body surface area, the relationship between size and energy loss linearized, although an increase can still be appreciated after 3.25 cm/m2. Energy loss pulled 1 sample off the trend line conspicuously as an outlier (red square). Box (A) shows the abnormal histologic features of the outlying sample, including fragmented elastin (black), disorganized smooth muscle cells (purple), and large amounts of disorganized collagen (yellow/brown). The green square represents a sample with a similar indexed aortic size, and box (B) shows the corresponding histologic features, with orderly elastic lamellae, orderly smooth muscle cells, and only moderate amounts of collagen.
The Journal of Thoracic and Cardiovascular Surgery  , DOI: ( /j.jtcvs )
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